The pipe set into the bar pad is the breather, there is a roll pin in the centre to keep it in, the pipe is open and without the guide bar on it will leak chain oil, the idea is once the bar is fitted this will then stop the leaking, not the best idea in the world, they are prone to emptying there oil tanks if left with a full tank, you can get at the other end of the pipe through the oil filler hole, gently screw a self tapping screw into the end, it should breath around the screw threads, do not tighten it right up or you will create a vacume the tank.
ADW
September 2010
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